1. Field of the Invention
The present invention relates generally to a method of securing and supporting items, such as applique (auxiliary) armor panels to an armored vehicle surface.
2. Description of the Prior Art
When an armored vehicle is hit by a projectile, the outer armor plate is damaged. Accordingly, such vehicles have been designed to include applique panels which provide additional protection against projectiles, and which can be readily removed and replaced.
Applique armor may be mounted on many types of military vehicles, as well as a multitude of other types of structures using spacer support systems. Over the years, the applique armor designed for such structures has been tailored for each application taking into account distinctive characteristics and operating conditions, such as ballistic loading, vibrations and noises, etc. In providing applique armor for each vehicle type, it is desirable that the system for attaching armor be capable of each adaptation and adjustment to a particular armor/vehicle system and its dynamic conditions. In particular, the method used for fastening applique armor to a vehicle must be light weight and engineered to meet load and shock requirements.
Over the years, a number of devices have been employed to hang armor on the surfaces of military vehicles. Examples of such devices are shown in U.S. Pat. No. 2,283,484 to Bak, U.S. Pat. No. 4,167,889 to Bohnue et.al., U.S. Pat. No. 4,716,810 to DeGuvera, and U.S. Pat. No. 4,833,968 to Bohnue et.al.
One means, in particular, for attaching applique armor panels involves the use of a stand-off cone. When the cone is made from the appropriate material, the triangular shape of the cone provides the needed geometric configuration to achieve a high strength-to-weight ratio. The preferred material for the cone include lightweight metals, such as aluminum, magnesium or titanium.
The strength of the stand-off cone is a function of both material strength and cross sectional properties, which include the cross sectional moment of inertia. Specifically, the moment of inertia increases at the forth power of the hollow cone's diameter. By increasing the diameter, one reduces significantly the amount of cone material needed to support items on a host surface. The consequent reduction in material leads to a reduction in weight.
There are various means for attaching such cones to the surface of the armored vehicle. One such fairly common method for hanging armor panels on military vehicles involves utilizing a cone which is attached to the hull of the vehicle by a centrally located stud or pin. Since the base of the cone could shift under transverse loading, the stud must be loaded in shear as well as tension. A design that could accommodate such a condition requires heavy cross sections of the stud. However, this reduces the weight efficiency. An alternative design must be provided which provides the needed loading without compromising weight efficiency.
Furthermore, the centrally located studs used in such designs are subjected to dynamic loads imparted by the weight of the armor when the vehicle is in motion. After repeated cycles, these loads cause the studs to bend or tear from the hull of the vehicle. A mounting scheme is need that is simple, cost effective, and includes a stabilizing feature to overcome this design fault.